Buy on board

A United Airlines Bistro on Board sandwich
An Air Asia X Pak Nasser's nasi lemak box

In commercial aviation, buy on board (BoB) is a system in which in-flight food or beverages are not included in the ticket price but are purchased on board or ordered in advance as an optional extra during or after the booking process. Some airlines, including almost all low-cost carriers and a handful of flag carriers, have buy-on-board food and beverages as part of their ancillary revenue generation.